Melting Icebergs Experiment

Would the planet Earth experience global flooding if the polar ice caps melted? In order to examine this question more deeply I conducted an investigation called the Melting Iceberg Experiment (Laureate, 2010). In this investigation a model is created using a block of ice, representing icebergs, floating in a bowl of water, representing the ocean. I placed the block of ice in the bowl of water and filled the bowl until it was about to overflow, then I waited for the ice to melt to see if the water would overflow.

Ultimately there was no overflow due to the melting of the ice. The only overflow noted during observation was a result of the shifting of the ice block during melting creating a disturbance in the water and causing the overflow. The reasoning is that the volume of water is the same no matter what state of matter it is in. Therefore, when the ice was floating in the water it had displaced as much water as it needed to make it float, and the melting was simply taking that volume of frozen water and changing phases to liquid water. The amount of water introduced into the system did not change, only the form of water within that system changed.

So how does this relate to the polar ice caps? To examine that we first need to determine if our model was an accurate representation of the actual system created in the natural world. In an over generalized view, the Arctic ice cap is compacted snow and ice floating in the middle of the Arctic Ocean. So it would seem that our model would represent the arctic ice cap on a very basic scale. The South Pole ice cap, however, consists of large glaciers resting atop a continental landmass. This also holds true for other areas of the world such as Greenland, Iceland, northern Canada, Alaska, the Soviet Union, and in the south the far reaches of Argentina and Chile. Should these ice covered lands melt, the runoff would add a new volume of water to the existing oceans and could then cause coastal lowlands worldwide to experience some sort of flooding.

This then begs the questions; could we create a model that represents more accurately the current state of the ice caps with some ice not originally in the water and some ice starting in the water? And, what kind of results would we get if we reversed the process? In a time of global cooling the ice sheets would then get larger turning more of the water into ice. Given the data collected and results from the investigation, would that process then cause the water of the coastline to recede? My favorite thing to tell my students when they ask questions like this is that there is only one way to find out. Let's test it.

References

Laureate Education, Inc. 2010. Melting Icebergs Experiment. Baltimore: Author.